Bacteria May Cause Colon Cancer

December 28th, 2014

People who have dense biofilm colonies of bacteria in the right colon (first part) are five times more likely to have malignant colon cancer and pre-malignant colon polyps, compared to those who have no biofilms (Proceedings of the National Academy of Sciences, Dec. 16, 2014). To diagnose biofilms, the authors developed a fluorescent technique to stain the biopsy specimens. If this research is supported by future studies, doctors will be able to check you for developing colon cancer long before it would normally be detected. Most colon cancers develop over five to ten years, and colon cancer is usually a curable disease if it is diagnosed early enough.

In humans, a bacterial biofilm is a mucilaginous coating that bacteria secrete around themselves to protect them from your immunity so they can live permanently inside your body. Other examples of biofilms include dental plaques in the mouth and the slime that covers stagnant pools or standing water.

The Study
The researchers examined healthy and cancerous tissue from 120 people taken during colonoscopies, where small pieces of tissue are removed to look for malignant changes in the inner linings of the colon. They found biofilms in 89 percent of tumors removed from the right colon (the first part), and in only 12 percent of tumors removed from the left side of the colon (the last part).

Dense bunches of bacterial biofilms are found on most colon polyps and colon cancers. The presence of these biofilms increases the chances of a person developing colon cancer and could offer a new way to predict who will develop colon cancer.

How the Foods You Eat Affect Gut Bacteria
Your diet determines which types of bacteria live in the first part (right side) of the colon. Bacteria that live in the last part (left side) of your colon have already had their food changed by the bacteria that live in the first part of the colon.

The food that you eat must be broken down into its basic building blocks before it can be absorbed into your bloodstream. Carbohydrates must be broken down into single sugars, proteins into amino acids, and fats into fatty acids. Foods that are not broken down and absorbed in the intestines pass along to reach your colon. There, bacteria can break down some of these foods that you could not absorb and use them to supply their energy. Bacteria that cannot break down the food that you eat will not thrive there. That means that bacteria in the first part of your colon are the ones that grow and thrive, “eating” the non-absorbable food that you have eaten. The types of foods that you eat determine which types of bacteria grow in the right side of your colon. Bacteria in the last part your colon get food that has already been changed by bacteria in the first part.

What This Means for You
Many previous studies have shown that increased risk for colon cancer is associated with:
• eating red meat and processed meats,
• eating fried foods,
• smoking,
• drinking alcohol,
• not exercising, or
• being overweight.
This groundbreaking study could lead to understanding how red meat, processed meats and fried foods, and perhaps other types of foods that have not yet been identified, cause biofilm colonies of bacteria to thrive in your colon. Further studies are needed to see whether the biofilm bacteria have a role in causing colon cancer or are just innocent bystanders.